A mixture of 3,5-dichloro-6-ethylpyrazine-2-carboxamide (200 mg), 3-chloro-4-methylsulfonylaniline (374 mg) and NMP (1 mL) was stirred at 230° C. for 1 hour using a microwave reaction system. Thereafter, trans-4-aminocyclohexanol (524 mg) was added to the reaction liquid and stirred at 190° C. for 30 minutes using a microwave reaction system. After cooling, the reaction liquid was partitioned using ethyl acetate and water, and the organic layer was washed with saturated aqueous sodium hydrogen carbonate and saturated aqueous sodium chloride. After drying over anhydrous magnesium sulfate, the solvent was distilled off, and the residue was purified by silica gel column chromatography (eluent; chloroform:methanol=10:0 to 30:1) to give a crude product. This product was heated with ethanol and washed to give a light yellow solid. To the light yellow solid, ethyl acetate was added and heated, and insoluble materials were separated by filtration and the filtrate was concentrated. After the filtrate was concentrated, the residue was heated and washed with ethanol to give 3-{[3-chloro-4-(methylsulfonyl)phenyl]amino}-6-ethyl-5-[(trans-4-hydroxycyclohexyl)amino]pyrazine-2-carboxamide (39 mg) as a light yellow solid.
